Inhibition of connexin hemichannels alleviates neuroinflammation and hyperexcitability in temporal lobe epilepsy.

Temporal lobe epilepsy (TLE) is one of the most common types of epilepsy, yet approximately one-third of patients are refractory to current anticonvulsive drugs, which target neurons and synapses. Astrocytic and microglial dysfunction is commonly found in epileptic foci and has been shown to contribute to neuroinflammation and hyperexcitability in chronic epilepsy. Accumulating evidence points to a key role for glial hemichannels in epilepsy, but inhibiting both connexin (Cx) gap junctions and hemichannels can lead to undesirable side effects because the former coordinate physiological functions of cell assemblies. It would be a great benefit to use an orally available small molecule to block hemichannels to alleviate epileptic symptoms. Here, we explored the effect of D4, a newly developed compound that inhibits the Cx hemichannels but not Cx gap junctions using the pilocarpine mouse model of TLE. In vitro application of D4 caused a near-complete reduction in the pilocarpine-induced cell membrane permeability associated with increased Cx hemichannel activity. Moreover, preadministration of D4 in vivo effectively reduced neuroinflammation and altered synaptic inhibition, which then enhanced the animal survival rate. Posttreatment with a single dose of D4 in vivo has prolonged effects on suppressing the activation of astrocytes and microglia and rescued the changes in neuroinflammatory and synaptic gene expression induced by pilocarpine. Collectively, these results indicate that targeting Cx hemichannels by D4 is an effective and promising strategy for treating epilepsy in which neuroinflammation plays a critical role.

Training for Pediatric Cardiac and Pulmonary Point of Care Ultrasound in Eastern Uganda.

Caring for children with acute illness is a challenge in limited-resource settings, especially when diagnostic imaging is limited or unavailable. We developed a training program in cardiac and lung point-of-care ultrasound (POCUS) for pediatric patients in eastern Uganda. Fourteen trainees including physicians, resident physicians and midlevels received training in cardiac and lung POCUS. Training included formal lectures, hands-on skills practice and individualized teaching sessions. Assessment included written knowledge assessment, direct observation and longitudinal image review. Blinded review of 237 consecutive ultrasound studies revealed satisfactory image quality (94.2% for lung and 93% for cardiac) and accurate image interpretation. Sensitivity and specificity of image interpretation were 0.93 (0.75-0.99) and 0.94 (0.78-0.99) for lung and 0.86 (0.71-0.95) and 0.94 (0.84-0.99) for cardiac compared with expert review. All trainees passed written knowledge assessments. After training, 100% of trainees reported that they would use POCUS in clinical activity and thought it would improve patient outcomes. Our training program indicated that trainees were able to perform high-quality cardiac and lung POCUS for pediatric patients with accurate interpretation. This builds a foundation for future studies addressing how POCUS can change outcomes for children in limited-resource settings.

Target-specific control of piriform cortical output via distinct inhibitory circuits.

Information represented by principal neurons in anterior piriform cortex (APC) is regulated by local, recurrent excitation and inhibition, but the circuit mechanisms remain elusive. Two types of layer 2 (L2) principal neurons, semilunar (SL), and superficial pyramidal (SP) cells, are parallel output channels, and the control of their activity gates the output of APC. Here, we examined the hypothesis that recurrent inhibition differentially regulates SL and SP cells. Patterned optogenetic stimulation revealed that the strength of recurrent inhibition is target- and layer-specific: L1 > L3 for SL cells, but L3 > L1 for SP cells. This target- and layer-specific inhibition was largely attributable to the parvalbumin (PV), but not somatostatin, interneurons. Intriguingly, olfactory experience selectively modulated the PV to SP microcircuit while maintaining the overall target and laminar specificity of inhibition. Together, these results indicate the importance of target-specific inhibitory wiring for odor processing, implicating these mechanisms in gating the output of piriform cortex.

Leadership Matters: Needs Assessment and Framework for the International Federation for Emergency Medicine Administrative Leadership Curriculum.

OBJECTIVES: The objective was to research and develop a novel curriculum on administrative leadership development within the discipline of emergency medicine (EM) with the goal of establishing and implementing it through the world's EM professional organizations. METHODS: From 2016 to 2018 an assessment of different administrative and leadership programs was performed by researching and reviewing previously outlined curricula. Using the data from this assessment, a questionnaire was developed, that was subsequently sent to members of the International Federation for Emergency Medicine's (IFEM) listserv. RESULTS: A total of 377 people from 38 different countries participated in the survey. The majority of respondents identified themselves as EM specialists (81%, 306/377), while others identified themselves as EM resident physicians (9.5%, 36/377) and non-EM specialist physicians (4.5%, 17/377). A large majority of respondents articulated that there was a paucity of developed curricula focusing on leadership, administrative, and management principles within their institution, training program, or professional organization. Across all topic areas, fewer than 30% of polled individuals indicated that they had formal education related to individual and programmatic leadership development, change management, assessment methodology, negotiation skills, financial analysis, media relations, and health care policy. Quality improvement (QI) was the only curricular element that a majority of respondents had integrated into their clinical practice (61%). Qualitative data analysis of the narrative comments was performed with further evaluation of thematic components. CONCLUSIONS: The results of this study further support the findings that the majority of EM providers queried do not have a longitudinal curriculum that fosters administrative and leadership development nor advocate for its importance in relation to the quality of care. Given this gap, we propose that medical education at all levels-medical schools, EM resident/specialty training programs, and professional organizations-should consider creating administrative and leadership development programs. Additionally, development of any curriculum should require a global understanding of health care systems and awareness of the unique contexts of a given location and its available resources.

Magnetic resonance imaging versus computed tomography and ultrasound for the diagnosis of female pelvic pathology.

OBJECTIVES: We sought to determine the diagnostic accuracy of magnetic resonance (MR) imaging compared with computed tomography (CT) and ultrasound (US) when evaluating for five common pelvic pathologies among women presenting to the emergency department (ED) with right lower quadrant abdominal pain. METHODS: This prospective, single-center study was conducted at an academic ED as a sub-analysis of a direct comparison of the diagnostic accuracy of CT and MR in the evaluation of appendicitis. Patients were eligible for participation in the parent study if they were at least 12 years old and had a CT performed for evaluation of possible appendicitis. In the current study, only female patients who also underwent pelvic US were included. Three radiologists independently interpreted each MR examination specifically for the presence of pelvic pathology, knowing that patients had initially undergone imaging evaluation for possible appendicitis. The determination of an independent expert panel of two radiologists and one emergency physician based on surgical pathology, comprehensive chart review, clinical information, and follow-up phone calls served as the reference standard. Test characteristics of MR, CT, and US were calculated based on this; the main outcome measure was the summary sensitivity and specificity of MR versus CT and US. RESULTS: Forty-one participants were included with a mean age of 27.6 ± 10.8 years. The MR consensus interpretation had an overall sensitivity and specificity of 57.1% (CI 38.8-75.5%) and 97.2% (CI 94.7-99.6%) respectively, for detecting any of the five pelvic pathologies. By comparison, CT exhibited sensitivity and specificity of 66.7% (CI 50.0-83.5%) and 98.3% (CI 96.4-100.0%) while it was 64.3% (CI 46.5-82.0%) and 97.7% (CI 95.6-99.9%) for US, respectively. No significant differences were identified when comparing these modalities. Overall, Fleiss' kappa interrater reliability value for MR interpretation was 0.75, corresponding to substantial agreement between the three readers. CONCLUSIONS: In women who might otherwise undergo multiple imaging tests to evaluate gastrointestinal versus pelvic pathologies, our data suggest that MR may be an acceptable first-line imaging test.

Chromium-mediated apoptosis: involvement of DNA-dependent protein kinase (DNA-PK) and differential induction of p53 target genes.

Cellular stress and DNA damage up-regulate and activate p53, fundamental for cell cycle control, senescence, DNA repair and apoptosis. The specific mechanism(s) that determine whether p53-dependent cell cycle arrest or p53-dependent apoptosis prevails in response to specific DNA damage are poorly understood. In this study, we investigated two types of DNA damage, chromium treatment and gamma irradiation (IR) that induced similar levels of p53, but that mediated two distinct p53-dependent cell fates. Chromium exposure induced a robust DNA-dependent protein kinase (DNA-PK)-mediated apoptotic response that was accompanied by the rapid loss of the cyclin-dependent kinase inhibitor 1A (p21) protein, whereas IR treatment-induced cell cycle arrests that was supported by the rapid induction of p21. Inhibition of DNA-PK effectively blocked chromium-, but not IR-induced p53 stabilization and activation. In contrast, inhibition of ATM and ATR by caffeine had the inverse effect of blocking IR-, but not chromium-induced p53 stabilization and activation. Chromium exposure ablated p21 transcription but PUMA and Bax transcription was significantly enhanced compared to non-damaged cells. In contrast, IR treatment triggered significant p21 mRNA synthesis in addition to PUMA and Bax mRNA production. While chromium treatment enhanced the binding of p53 and RNA polymerase II (RNA Pol II) to both the p21 and PUMA promoters, RNA Pol II elongation was only observed along the PUMA gene and not the p21 gene. In contrast, following IR treatment, RNA Pol II elongation was observed on both p21 and PUMA. Chromium-induced apoptosis therefore involves DNA-PK-mediated p53 activation followed by preferential transcription of pro-apoptotic PUMA over anti-apoptotic p21 genes.

Hypersensitivity to chromium-induced DNA damage correlates with constitutive deregulation of upstream p53 kinases in p21-/- HCT116 colon cancer cells.

The cyclin-dependent kinase inhibitor p21(CIP1/WAF1) is a key component in cell cycle control and apoptosis, directing an anti-apoptotic response following DNA damage. Chromium exposure resulted in a 500-1000 fold increase in apoptosis-induced cell death in p21-/- HCT116 cells compared to wild-type or p53-/- cells. p53 shRNA (or transient p53 siRNA) into p21-/- HCT116 cells reduced Cr(VI) sensitivity, suggesting the enhanced apoptosis in p21-/- cells is p53-dependent. Under non-DNA damage conditions, the p53 level in p21-/- cells was significantly higher than in wild-type cells, due to enhanced p53 phosphorylation and stabilization rather than elevated p53 transcription. Wild-type cells showed significant p53 protein induction upon DNA damage whereas p21-/- cells showed no p53 increase. p21-/- cells display the constitutive activation of upstream p53 kinases (ATM, DNA-PK, ATR, AKT and p38). 2D gel analysis revealed p53 patterns in p21-/- cells were distinct from those in wild-type cells before and after chromium exposure. Our results suggest that p21 has an important role in the cellular response to normal replicative stress and its absence leads to a "chronic DNA damage" state that primes the cell for p53-dependent apoptosis.

The ATM-SMC1 pathway is essential for activation of the chromium[VI]-induced S-phase checkpoint.

Hexavalent chromium (Cr[VI]) is a common industrial waste product, an environmental pollutant, and a recognized human carcinogen. Following cellular uptake, Cr[VI] can cause DNA damage, however, the mechanisms by which mammalian cells respond to Cr-induced DNA damage remain to be elucidated. Using single cell gel electrophoresis (e.g., Comet Assay) and immunofluoresence microscopy to detect the presence of gamma-H2AX foci, we find that Cr[VI] induces DNA double-strand breaks similar to ionizing radiation (IR). We also demonstrated that ataxia telangiectasia mutated (ATM) is activated in response to Cr[VI] and exposure to Cr[VI] triggers a dose and ATM-dependent S-phase arrest. Further, we document that ATM is required for phosphorylation of the structural maintenance of chromosome protein 1 (SMC1). Finally, we find that ATM-dependent phosphorylation of SMC1 is required to facilitate S-phase cell-cycle arrest in response to Cr[VI] exposure. Collectively, these results indicate that the ATM-SMC1 pathway plays a critical role in cellular response to Cr[VI].

Genetic and cellular mechanisms in chromium and nickel carcinogenesis considering epidemiologic findings.

Genetic and environmental interactions determine cancer risks but some cancer incidence is primarily a result of inherited genetic deficits alone. Most cancers have an occupational, viral, nutritional, behavioral or iatrogenic etiology. Cancer can sometimes be controlled through broad public health interventions including industrial hygiene and engineering controls. Chromium and nickel are two human carcinogens associated with industrial exposures where public health measures apparently work. Carcinogenic mechanisms of these metals are examined by electron-spin-resonance-spectroscopy and somatic-mutation-and-recombination in Drosophila melanogaster in this report. Both metals primarily affect initiation processes in cancer development suggesting important theoretical approaches to prevention and followup.

Epidemiologic studies of PCB congener profiles in North American fish consuming populations.

Long range atmospheric and stream transport and oceanic currents drive the ecologic process of PCB deposition in the abiotic environment. In contrast short range transport via bioaccumulation-biomagnification up the food chain determines PCB congener profiles and concentrations and their adverse effects in biological organisms. Two research approaches to congeners, with potential to associate specific adverse human health effects with PCB concentrations in indigenous small populations, are summarized in this study. The field epidemiological approach includes giving questionnaires to target population groups in conjunction with sampling for PCBs (and selected persistent organic pollutants and metals), in foods purchased or hunted and collected by Inuit peoples. Direct determination of contaminant levels in food sources and among individuals in selected comparative subpopulations is also presented.

Short-Record-Based Extreme Wind Simulation.

In order to utilize limited historical wind records for estimating extreme wind speeds for natural hazards damage mitigation, a Markov chain model for generating long-term annual extreme winds, on the basis of short-term records, is investigated. Basically, this simulation model consists of three components. They are State of wind speeds, wind speed distribution functions, and transition probability matrices. The basic strategy of our simulation model is to generate the time series of hourly wind speeds in parts: for those winds associated with well-behaved climates and those with extreme winds. Applications of this model to generate long-term extreme winds, on the basis of short records at Houston Intercontinental Airport of Texas, arc demonstrated.